1. Field of the Invention
This invention relates to a graft modified polyethylene and a process comprising contacting polyethylene with a organic peroxide in the presence of an ethylenically unsaturated polycarboxylic acid or derivative thereof at a temperature of 140.degree.-210.degree. C.
2. Description of the Prior Art
Various observations have been made by the prior art regarding reactions between polyolefins with ethylenically unsaturated polycarboxylic acids using peroxy compounds as catalysts:
Fasce in U.S. Pat. No. 2,973,344, issued Feb. 28, 1961 which broadly describes the concept of contacting polyolefins with unsaturated .alpha.-.beta. dicarboxylic acid anhydrides in the presence of a peroxide catalyst to produce modified polymers having substantially increased melting points and very low solubility in nonpolar solvents;
Wu et al. U.S. Pat. No. 3,873,643, issued Mar. 25, 1975, which describes a process for the preparation of graft copolymers of polyolefins and at least one monomer selected from the class of polymerizable cyclic or polycyclic ethylenically unsaturated acids or acid anhydrides prepared by grafting the monomer to the polyethylene in the presence of hydroperoxides or other free radical catalysts at a temperature above the melting point of polyolefin;
Japan publication Sho 45/1970-30943, dated Oct. 7, 1970, which describes modifications of polyolefin blends by addition to the two component blends of polyolefin contacted with an unsaturated carboxylic acid or a derivative thereof such as anhydride of a carboxylic acid and dibenzoyl peroxide in a fused state; and
Japan publication Sho 50/1975-1198888, dated Sept. 19, 1975, which describes the process for modifying polyolefins by grafting maleic anhydrides onto the polyolefins in a molten state in the presence of a hydroperoxide.
Although the prior art focuses on graft modification of the polyolefins in the presence of peroxy compounds, heretofore prior art has not recognized an efficient graft modified polyethylene process wherein substantially all of the modifier processed with the polyethylene is grafted to the polymer backbone without deleteriously affecting the physical and chemical properties of the polyolefin.